The invention relates to a manually controlled metering pump for bottles with deformable sheaths.
Certain liquid or pasty products, particularly medications, are offered in bottles and must not be exposed to the air to keep their cleanliness or to avoid degradation. The bottles which contain them must thus have a deformable sheath, so that the volume of this sheath always corresponds to the volume of the liquid present in the bottle.
To dispense the liquid, it is known to use a screwed push button which is raised, then return it to place. It is also known to use a manually controlled pump having at its lower part an inlet ball valve and at its upper part an outlet ball valve. The pumps of this type operate correctly when maintained strictly upright.
If the bottle is on its side or inclined, the balls have the tendency to leave their conical seat and the pump does not ensure satisfactory sealing of the bottle.
There is also known from Patent Abstract of Japan, Vol. 13, No. 265, of Jun. 19, 1989 and JP-1-66,475, a metering pump adapted for very viscous fluids, comprising a metering chamber between a lower valve and an upper valve, a push button returned by a spring and a spout communicating with the metering chamber via the central channel.
The present invention has for its object to provide a pump ensuring sealing of the bottle no matter what its position.
The invention has for an object a manually controlled metering pump for a bottle with a deformable sheath, comprising a metering chamber comprised between a lower valve and an upper valve, a push button returned by a spring and a spout communicating with the metering chamber via a central channel, the upper valve being carried by a disc constituting the base of a hollow rod secured to the push button, and bearing from below on a hollow piston adapted to be driven by the push button, and sliding in the metering chamber, characterized in that the lower valve is flexible, of truncated conical shape and is maintained on the bottom of the pump by a key, in that the hollow piston has a constriction on which comes to bear a central tube carried by the push button and in that the hollow rod is enlarged below the restriction, an O-ring seal being disposed between the enlargement of the hollow rod and the constriction.
According to other characteristics of the invention:
the hollow piston carries an O-ring to ensure sealing in the metering chamber. PA1 the O-ring is held in a groove carried by the hollow piston, PA1 the groove surrounds the O-ring on three sides; PA1 the groove maintains the O-ring from above and within it, and the O-ring is maintained from below by the edge of the disk constituting the base of the hollow rod; PA1 the lower valve is carried by a truncated conical portion of the bottom of the pump.